Dehydrator for petroleum emulsions



March 5, 1929. J. H. c. DE BREY 1,704,463

DBHYDRATOR FOR PETROLEUM EHULSIONS Filed July 20. 1926 Patented Mar. 5, 1929.

UNITED STATES PATENT OFFICE.

JAN HEINRICH CHBISTOPH DE BREY, OF THE HAGUE, NETHERLANDS.

DEHYDRATOR FOR PETROLEUM EMULSIONS.

Application filed July 20,

My invention relates to the art of dehydratmg petroleum emulsions.

It is a well known fact that petroleum emulsions when subjected to the action of an electric field tend to break up, the water particles ag lomeratin to form large masses which settle out reac ily by the action of gravity.

It is also a well known fact that in many oilsthe dehydrating action is facilitated by a movement of one of the electrodes or by an agitation of the material being treated.

It isa further well known fact that where electrodes upon which high electrical potentials are impressed are immersed in oil that there is considerable danger of electric discharges taking place over the surface of the oil with the result that in the ordinary open type of dehydrator fires are frequent occurrences.

It is also well known to provide a dehydrator in which the fluid being treated is exeluded from direct contact with the air. thus eliminating the danger of fire and conserving the lighter oil vapours. To this end the top of the dehydrator tank is closed by a cover.

It is further well known to use alternating current to produce the electric field and to interrupt this current periodically.

it is also known to provide doors in the upper part of the dehydrator which allow escape of any gases formed in the treater, for instance by explosion.

It is also known to use pulsating currents the peak voltage of which is a multiple of and at least double the effective voltage.

In the known dehydrators with a moving electrode in which the oil being treated is excluded from direct contact with the air the inner electrode is insulated from the outer shell of the apparatus by an insulation which is immersed wholly or partly in the oil. It. has been found, however. that insulators immersed in an emulsion of salt water in petroleum oil are liable to crack and break. To prevent this in a closed dehydrator there might be provided a suflicient gas space above the surface of the oil to permit the insulating means to be above the level of the emulsion.

' As this gas space, however, would nor- 1926. Serial No. 123,782.

mally contain an inflammable mixture of air and oil vapours, the danger of ex losion. the prevention of which is the chief o ject of the closed dehydrators, would be re-established.

The object of the present invention is to permit the insulating means in a dehydrator to be placed above the level of the Oil and at the same time to minimize the danger of explosion in the gas space above the 011.

Further objects and advantages of the invention will be made evidenthereafter.

Referring to the drawings, which are for illustrative purposes-only:

Fig. 1 is a sectional elevation of my invention.

F ig. 2js a plan on the line II-II of Fig. I viewed from above.

Fig. 3 is a plan on the line III-III of Fig. I viewed from above.

In the drawings:

1 is a dehydrating tank;

2 is a cover on said tank;

3 is a central casing on said cover, opening into the tank 1 and further closed;

4 is a rotating inner electrode suspended in and electrically connected to a fixed sleeve 5 having arms6, each of which is supported by an insulator 7, the insulators being supported by an annular member 8 supportedby brackets 9 attached to the wall of the casing.

Above the sleeve 5 the inner electrode has a knob 10 with spider arms 11. Between the knob 10 and the sleeve 5 is a ball bearing 12. Electric current is provided to the sleeve 5 by a cable or wire 13 which passes through the wall of the casin bv an insulator 14. The spider arms 11 of the knob 10 are connected by vertical insulators 15 to a disc 16 which is connected by flexible connection to a parallel disc 17 provided with flat springs 18 engaging with extension 19 upon the disc 16. The disc 17 is rotated by a shaft 20 which is moved by a wormwhcel 21 and worm 22, actuated by a motor 23 mounted on the top of easing 3.

The casing 3 has a manhole 24 giving access to the parts of the electrode 4 above the sleeve 5.

of the casing 3.

Each aperture is closed by a plate 26 consisting of an iron flange 27 corresponding to the flange of the aperture, to which a thin plate of zinc 28 has been soldered so as to constitute a closing which yields if an explosion takes place in the interior of the casing and then provides a wide outlet for the escape of gases. The dimensions of said apertures may be for instance 850 x 500 mm. The thickness of the zinc may be 0,25 mm. These dimensions are suitable for a 'asing of 850 mm. internal diameter and a total height of about 3500 mm. The part of the casing below the brackets 8 is provided with pet cocks 30, 31.

The electrode at extends into the tank 1 and carries there a system of connected rods 4r1 l243-44 forming the active part of the electrode. The shift of the electrode from a point below the sleeve 5 to a point above the rods 41 is protected and insulated by a quartz tube 32, 33 fixed to the electrode by means of ebonite rings 34, 35, 36 with ebonite screws. This protection prevents the formation of currents or discharges between this part of the electrode and the walls of the casing 3 or the tank 1.

The tank 1 has a steam coil 45 near the bottom, an outlet for oil and water 46, oil inlets 47, manholes 48, pet cocks 49, 50, 51 and tubes for thermometers 5253. Secured to the upper part of the casing 3 is a pressure safety valve 5d. The level of the oil in the apparatus is between the pet cocks 30 an d 31.

The apparatus is operated as follows:

Crude emulsion is fed into tank 1 by the oil inlets 4:7 and the apparatus is filled until it is entirely filled up to above the pet cock 31. The air escapes by the safety valve 54:. The oil is heated by the steam coil &5 to the desired temperature.

An interrupted potential is now applied to the electrode 4. The current passes from the cable 13 through the insulator 14 to the arms 6 of the sleeve 5, and from sleeve 5 to the rotating shaft 4 with its rods 414243 4:4. From the rods 42 it passes through the emulsion to the walls of the tank 1, thereby disrupting the water droplets and de-emulsifying and setting free the trapped Water.

The de-emulsified mixture of oil and water is discharged by 46 to a settling tank (not shown) whilst the level in the apparatus is maintained by adding fresh emulsion through 47. The emulsion is heavier than the purified oil, therefore the upper part of tank 1 and the casing will only contain purified oil with very little Water.

The insulators, which insulate the inner electrode from the casing 3 never come into contact with emulsion and are thus protected against cracking and breakage.

The space in casing 3 above the level of the oil may contain sometimes an inflammahle mixture of air and hydrocarbon vapours, the composition of which will depend on the nature of the crude oil and the temperature,

but it is very unlikely that this mixture will be exploded by electric discharges passing over the surface of the oil. In the first place the oil in the casing is nearly water free, in the second place the electrode is protected by a quartz tube. The discharge would have to take its course over the surface of the quartz tube and over the ebonite ring 3%..

If, however, notwithstanding these precautions an explosion occurs, the zinc plates 28 will immediately yield and the exploding gases will escape without damaging the apparatus.

The apparatus is preferably used with a pulsating alternating current, having short periods of high potential. When such current is used the apparatus is suitable for breaking up even the most refractory emulsions. The electrodes should rotate with a suflicient speed to keep the whole of the emulsion in a moderate motion, which is not too violent to prevent the dehydrated oil to collect in the upper space of the tank and in the casing whilst the mixture of oil and freed water is discharged from the tank to a settling tank not shown) in which the water separates from the oil.

\Vhat I claim is 1. A dehydrator for petroleum emulsions, comprising a wide tank, a cover on the top of said tank having a central open aperture and surmounted by a central casing around this aperture, a centrally disposed electrode in said casing and extending into said tank and means for insulating said electrode from said casing entirely disposed in the upper part ot said casing well above the highest level of the oil in the apparatus.

2. A dehydrator for petroleum emulsions, comprising a wide tank, a cover on the top 0 i said tank, having a central open aperture and a surmounting central casing around this aperture on said cover, a centrally disposed electrode in said casing and extending into said tank, means for insulating said electrode from said casing entirely disposed in the upper part of said casing well above the highest level of the oil in the apparatus and apertures located in said central casing and closed with thin plates which open under internal pressure, said apertures being of sufficient size to allow the immediate escape of gases produced by an explosion within the apparatus.

3. A dehydrator for petroleum emulsions comprising a wide tank, a cover on the top of said tank, having a central aperture and sin mounted by a central casing around this aperture, a centrally disposed electrode in said cas ing and extending into said tank, means for insulating said electrode from said casing disposed in the upper part of said casing and apertures closed by thin zinc plates, disposed in the upper art of said casing.

4. A dehydrator for petroleum emulsions casing disposed entirely in the upper part of said casing. means for controlling the level of the 011 in the lower part of said casing to prevent contact of the oil wlth said insulating means and apertures closed with thin plates which open under internal pressure disposed in the upper part of said casing.

5. A dehydrator for petroleum emulsions, comprising a wide tank, a cover on the top of said tank, having a central open aperture and surmounted by'a central casing around this aperture, a centrally disposed electrode in said casing and extending into said tank, means for insulating said electrode from said casing disposed entirely in the upper part of said casing well above the highest level of the oil in the apparatus, means for applying a pulsating alternating current on said electrode and means for limiting the damage of explosion in the upper part of said casing,

6. A dehydrator for petroleum emulsions, comprising a wide tank, a cover on the top of said tank, having a central open aperture and surmounted by a central casing around this aperture, a centrally disposed electrode in said casing and extending into said tank, a sleeve in the upper part of said casing, by which said electrode is rotatably supported, insulators supporting said sleeve and a member connected to the frame of said casing which supports said insulators.

7. A dehydrator for petroleum emulsions, comprising a wide tank, a cover on the top of said tank having a central open aperture and surmounted by a central casing around this aperture, a centrally disposed electrode in said casing and extending into said tank, a sleeve in the upper part of said casing by which said electrode is rotatably supported, insulators sup orting said sleeve, a member connected to 51s frame of said casing supportin said insulators, an insulator passing through the wall of the casin through which passes a conductor electrical connected to said sleeve and thereby to sai electrode.

8. A dehydrator for petroleum emulsions comprising a wide tank, a cover on the top of said tank having a central aperture and surmounted by a central casing around this aperture, a centrally disposed electrode in said casing and extending into said tank, a sleeve supporting said electrode means for supporting said sleeve insulated from the casing, means for carrying currents through the wall of said casing to said sleeve and from said sleeve to the electrode, a knob with spider arms connected to the electrodes above said sleeve, insulators connecting said spider arms to a rotating disc and means for rotating said disc.

9. A dehydrator for petroleum emulsions comprising a wide tank, a cover on the top of said tank having-a central aperture and surmounted by a central casing around this aperture, a centrally disposed electrode in said casing and extending into said tank, said electrode being supported by an insulated sleeve in the upper part of said casing and having a knob with spider arms above said sleeve, insulators connecting said spider arms to a rotating disc having projections engaged by flat springs on a parallel rotatin disc, a shaft for rotating said disc whic passes through the top of the casing and means for rotating said shaft.

10. A dehydrator for petroleum emulsions comprising a wide tank, a cover on the top of said tank having a central aperture and surmounted by a central casing around this aperture, a centrally disposed electrode in said casing and extending into said tank, means for controlling the level of the oil in the lower part of said casing, an electrically connected insulated sleeve supporting said electrode in the upper part of said casing, said electrode having a knob above said sleeve connected by insulators to a flexible system of rotatable discs and means for rotating said discs on the top of said casing.

11. A dehydrator for petroleum emulsions comprising a wide tank, a cover on the top of said tank having a central aperture and surmounted by a central casing around this aperture, a centrally disposed electrode in said casing and extendin into said tank, means for controlling the evel of the oil in the lower part of said casing, a quartz tube surrounding the shaft of said electrode in the lower part of said casing and the upper part of said tank, an electrically connected insulated sleeve supporting said electrode in the upper part of said casing, closed apertures in the upper part of said casing which open under internal pressure, a knob on the top of said electrode above the sleeve and being connected by insulators to a flexible system of rotatable discs and means for rotating said discs on thetop of said casing.

12. A dehydrator for petroleum emulsions comprisin a wide tank, a cover on the top of said tank having a central aperture and surmounted by a central casing around this aperture, a centrally disposed electrode in said casing and'extending into said tank, oil inlets in said tank above the eflective part of the electrode, a heating coil in the lower part of said tank, a discharge opening in the lower art of said tank, means for controlling the evel of the oil in the lower art of said casing, a quartz tube surrounding the shaft of the electrode in the lower part of the easing and the upper part of the tank and being connected to the electrode by ebonite rings, nected by insulators to a rotatable member an electrically connected insulated sleeve supconnected to a shaft which passes through porting said electrode in the-upper part of the top of the casing and a pressure safety 10 said casing. closed apertures in the npper valve connected with the top of said casing.

part Of said casing WlllCh open under lIltBP- In tegtinqony whereof, I affix my signature nal pressure, a member on the top of sa1d electrode above said sleeve and belng con- JAN HEINRICH CHRISTOPH de BREY. 

